Dark-field annular lighting device and optical detection system

Abstract

The embodiment of the invention provides a dark field annular lighting device and an optical detection system, and relates to the technical field of optics. According to the dark field annular lighting device, a light source is used for outputting a lighting beam, and the lighting beam is split into a first light beam and a second light beam through a prism light splitting unit; the light path transmission unit comprises a first reflecting mirror and a second reflecting mirror, the first reflecting mirror is used for reflecting the first light beam to the light path turning unit, and the second reflecting mirror is used for reflecting the second light beam to the light path turning unit; the light path turning unit is used for changing the transmission directions of the first light beam and the second light beam and transmitting the first light beam and the second light beam to the annular illumination shaping unit; the annular illumination shaping unit is used for modulating the first light beam and the second light beam into an arc shape and splicing the arc shape into an annular illumination view field to a measured object. According to the dark field annular lighting device provided by the embodiment of the invention, the light beam transmission efficiency is improved, and the omni-directional defect detection capability is ensured.

Description

Technical Field

[0001] The present invention relates to the field of optical detection technology, and in particular to a dark field annular lighting device and an optical detection system. Background Art

[0002] Optical detection methods occupy an absolute dominant position in the field of semiconductor detection. Among them, the scheme in which the imaging system receives the target's transmitted or reflected light is called the bright field scheme, and the scheme in which the imaging system receives the target's scattered light is called the dark field scheme. Since the scattered light signal of the dark field scheme is much smaller than the reflected light signal of the bright field, the illumination intensity of the light source and the energy transmission efficiency of the system are higher.

[0003] In the dark field solution, a single-phase light source will lose its effect on defects at a specific angle, so a ring light source is generally used in the dark field solution at this stage. In the prior art, in order to convert an ordinary light source into a ring light source, optical fiber is required, which will greatly attenuate the light intensity of the light source, and the light intensity attenuation may even exceed 50%. The large attenuation of light intensity may lead to insufficient lighting intensity and waste of energy. Summary of the invention

[0004] The embodiments of the present invention provide a dark field annular lighting device and an optical detection system, which improve the light beam transmission efficiency and ensure the omnidirectional defect detection capability.

[0005] On the one hand, an embodiment of the present invention provides a dark field annular lighting device, including a light source, a prism light splitting unit, an optical path transmission unit, an optical path deflection unit and an annular lighting shaping unit;

[0006] The light source is used to output an illumination light beam, and the illumination light beam is split into a first light beam and a second light beam by a prism light splitting unit;

[0007] The optical path transmission unit includes a first reflector and a second reflector, the first reflector is used to reflect the first light beam to the optical path deflecting unit, and the second reflector is used to reflect the second light beam to the optical path deflecting unit;

[0008] The optical path deflection unit is used to change the transmission directions of the first light beam and the second light beam, and transmit the first light beam and the second light beam to the annular lighting shaping unit;

[0009] The annular lighting shaping unit is used to modulate the first light beam and the second light beam into an arc shape and splice them into an annular lighting field of view to the object to be measured.

[0010] Optionally, the light path transmission unit includes a convex reflector, and the annular illumination shaping unit includes an aconic lens;

[0011] The first light beam and the second light beam are divergently reflected by the convex reflector to the axle lens, and the axle lens modulates the received light beams into an annular illumination field.

[0012] Optionally, the convex reflector includes a first convex reflector and a second convex reflector, the first convex reflector reflects the first light beam, and the second convex reflector reflects the second light beam; or the convex reflector includes a hollow convex reflector, and the first light beam and the second light beam are both reflected by the hollow convex reflector.

[0013] Optionally, the optical path transmission unit includes a concave reflector, and the annular illumination shaping unit includes a spherical reflector group;

[0014] The first light beam and the second light beam are converged and reflected to the spherical reflector group through the concave reflector, and the spherical reflector group modulates the received light beams into a ring-shaped illumination field of view.

[0015] Optionally, the concave reflecting mirror includes a first concave reflecting mirror and a second concave reflecting mirror, the first concave reflecting mirror reflects the first light beam, and the second concave reflecting mirror reflects the second light beam; or the concave reflecting mirror includes a hollow concave reflecting mirror, and the first light beam and the second light beam are both reflected by the hollow concave reflecting mirror;

[0016] The spherical reflector group includes a central convex spherical reflector and a first concave spherical reflector and a second concave spherical reflector located on both sides of the central convex spherical reflector. The light reflected by the concave reflectors converges to the central convex spherical reflector. The reflected light of the central convex spherical reflector is reflected by the first concave spherical reflector or the second concave spherical reflector to form a ring-shaped illumination field.

[0017] Optionally, the number of light sources, prism splitting units and optical path transmission units is at least two, and the annular illumination shaping unit modulates the output light beams of at least two light sources into an arc shape and splices them into an annular illumination field to the object to be measured.

[0018] Optionally, the dark field annular lighting device further comprises a collimating and homogenizing unit, which is located between the light source and the prism splitting unit. The illumination light beam output by the light source is collimated by the collimating and homogenizing unit and then incident on the prism splitting unit.

[0019] Optionally, the dark field annular lighting device further includes an imaging optical path unit and a camera, and the light from the object to be measured or scattered light is incident on the imaging optical path unit and converges to an imaging surface of the camera through the imaging optical path unit.

[0020] Optionally, the outer contour diameter of the imaging optical path unit is smaller than the minimum inner diameter of the optical path deflecting unit and the annular illumination shaping unit, and the imaging optical path unit is surrounded by the optical path deflecting unit and the annular illumination shaping unit.

[0021] On the other hand, an embodiment of the present invention further provides an optical detection system, comprising the dark field annular lighting device provided by any embodiment of the present invention.

[0022] The dark field annular lighting device provided in the embodiment of the present invention uses a prism splitting unit to split the illumination light beam, avoiding the use of optical fiber, thereby avoiding energy loss when the light beam is coupled into and out of the optical fiber, and reducing the loss during the light beam transmission process, thereby improving the light beam transmission efficiency; the split light beam is modulated into an annular light beam through the optical path deflection unit and the annular lighting shaping unit, forming a dark field annular lighting on the detection surface of the object to be measured, so that the detection surface is illuminated by light beams in all directions, ensuring omnidirectional defect detection capabilities.

[0023] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solution in this embodiment, the drawings required for use in the description of the embodiment will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 is a structural schematic diagram of a dark field annular lighting device provided by an embodiment of the present invention;

[0026] Figure 2 is a light splitting optical path diagram of a prism light splitting unit provided in an embodiment of the present invention;

[0027] Figure 3 is a schematic structural diagram of another dark field annular lighting device provided by an embodiment of the present invention;

[0028] Figure 4 is a structural schematic diagram of another dark field annular lighting device provided by an embodiment of the present invention;

[0029] Figure 5 is a structural schematic diagram of another dark field annular lighting device provided by an embodiment of the present invention;

[0030] Figure 6 is a structural schematic diagram of another dark field annular lighting device provided by an embodiment of the present invention;

[0031] Figure 7 is a structural schematic diagram of another dark field annular lighting device provided by an embodiment of the present invention;

[0032] Figure 8 is a structural schematic diagram of another dark field annular lighting device provided by an embodiment of the present invention;

[0033] Fig. 9is a schematic diagram of a three-dimensional structure of a dark field annular lighting device provided by an embodiment of the present invention;

[0034] Fig.10 It is a top view schematic diagram of an imaging optical path unit, an optical path deflection unit and an annular illumination shaping unit provided in an embodiment of the present invention;

[0035] Fig.11 It is a partial light path schematic diagram of a dark field annular lighting device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0037] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0038] Figure 1 is a schematic diagram of a dark field annular lighting device provided by an embodiment of the present invention, with reference to Figure 1 The embodiment of the present invention provides a dark field annular lighting device, including a light source 1, a prism splitting unit 2, an optical path transmission unit 3, an optical path bending unit 5 and an annular lighting shaping unit 6; the light source 1 is used to output an illumination light beam, and the illumination light beam is split into a first light beam and a second light beam by the prism splitting unit 2; the optical path transmission unit 3 includes a first reflector 31 and a second reflector 32, the first reflector 31 is used to reflect the first light beam to the optical path bending unit 5, and the second reflector 32 is used to reflect the second light beam to the optical path bending unit 5; the optical path bending unit 5 is used to change the transmission direction of the first light beam and the second light beam, and transmit the first light beam and the second light beam to the annular lighting shaping unit 6; the annular lighting shaping unit 6 is used to modulate the first light beam and the second light beam into an arc shape and splice them into an annular lighting field of view to the object to be measured 7.

[0039] refer to Figure 1 The illumination light beam emitted by the light source 1 may be parallel light, and the illumination light beam is incident on the prism splitting unit 2 . Figure 2 is a light splitting optical path diagram of a prism light splitting unit provided in an embodiment of the present invention, with reference to Figure 2 The prism splitter unit 2 includes a first incident surface 21, a second incident surface 22, and an exit surface 23. The first illumination light beam S1 incident on the prism splitter unit 2 from the first incident surface 21 is refracted when passing through the first incident surface 21, and the propagation direction is changed. Then, it is refracted again when it is emitted from the exit surface 23; and the second illumination light beam S2 incident on the prism splitter unit 2 from the second incident surface passes through the second incident surface 22 and the exit surface 23, and its propagation direction is also changed twice. Since the angles of the first incident surface 21 and the second incident surface 22 are different, the final exit angles of the first illumination light beam S1 and the second illumination light beam S2 are also different, so that the illumination light beam is divided into the first light beam and the second light beam. Reference Figure 1 The first light beam is reflected by the first reflector 31 to the light path deflecting unit 5, and the second light beam is reflected by the second reflector 32 to the light path deflecting unit 5. Then the first light beam and the second light beam enter the annular lighting shaping unit 6 after passing through the light path deflecting unit 5. The first light beam and the second light beam are respectively modulated into arc-shaped light beams by the annular lighting shaping unit 6 and are spliced ​​to form an annular light beam. Figure 3 is a schematic diagram of the structure of another dark field annular lighting device provided by an embodiment of the present invention, referring to Figure 3 , the illumination light beam emitted by the light source 1 is divided into a first light beam and a second light beam by the prism light splitting unit 2, and the first light beam and the second light beam pass through the optical path transmission unit ( Figure 3 Not shown), optical path deflection unit ( Figure 3 Not shown) and annular lighting shaping unit ( Figure 3 The images (not shown) are modulated and spliced ​​to form a ring-shaped illumination field.

[0040] The dark field annular lighting device provided in the embodiment of the present invention uses a prism splitting unit to split the illumination light beam, avoiding the use of optical fiber, thereby avoiding energy loss when the light beam is coupled into and out of the optical fiber, and reducing the loss during the light beam transmission process, thereby improving the light beam transmission efficiency; the split light beam is modulated into an annular light beam through the optical path deflection unit and the annular lighting shaping unit, forming a dark field annular lighting on the detection surface of the object to be measured, so that the detection surface is illuminated by light beams in all directions, ensuring omnidirectional defect detection capabilities.

[0041] Figure 4 is a schematic diagram of the structure of another dark field annular lighting device provided by an embodiment of the present invention, referring to Figure 4Optionally, the optical path transmission unit 5 includes a convex reflector 51, and the annular lighting shaping unit 6 includes a conical lens 61; the first light beam and the second light beam are divergently reflected by the convex reflector 51 to the conical lens 61, and the conical lens 61 modulates the received light beams into a ring-shaped lighting field of view.

[0042] refer to Figure 4 , the first light beam is reflected by the first plane mirror 31 to the convex reflector 5, and the second light beam is reflected by the first plane mirror 32 to the convex reflector 51. After the first light beam and the second light beam are reflected by the convex reflector 51, the conical lens 61 modulates the first light beam and the second light beam into the first arc-shaped light beam and the second arc-shaped light beam respectively, and the first arc-shaped light beam and the second arc-shaped light beam are combined to form a ring-shaped light beam. Optionally, the convex reflector 51 includes a first convex reflector and a second convex reflector, the first convex reflector reflects the first light beam, and the second convex reflector reflects the second light beam; or the convex reflector includes a hollow convex reflector, and the first light beam and the second light beam are both reflected by the hollow convex reflector. The specific implementation can be designed according to actual conditions.

[0043] Figure 5 is a schematic diagram of the structure of another dark field annular lighting device provided by an embodiment of the present invention, referring to Figure 5 Optionally, the optical path transmission unit 5 includes a concave reflector 52, and the annular lighting shaping unit 6 includes a spherical reflector group; the first light beam and the second light beam are converged and reflected to the spherical reflector group through the concave reflector 52, and the spherical reflector group modulates the received light beams into an annular lighting field of view.

[0044] refer to Figure 5 The first light beam is reflected by the first plane mirror 31 to the concave reflector 52, and the second light beam is reflected by the first plane mirror 32 to the concave reflector 52. The concave reflector 52 converges the first light beam and the second light beam and reflects them to the spherical reflector group. The spherical reflector group modulates the first light beam and the second light beam into a third arc-shaped light beam and a fourth arc-shaped light beam respectively, and the third arc-shaped light beam and the fourth arc-shaped light beam are combined to form a ring-shaped light beam.

[0045] Optionally, the concave reflector 52 includes a first concave reflector and a second concave reflector, the first concave reflector reflects the first light beam, and the second concave reflector reflects the second light beam; or the concave reflector includes a hollow concave reflector, and the first light beam and the second light beam are both reflected by the hollow concave reflector; the spherical reflector group includes a central convex spherical reflector 11 and a first concave spherical reflector 12 and a second concave spherical reflector 13 located on both sides of the central convex spherical reflector, and the light reflected by the concave reflector 52 (which can be two concave reflectors or a hollow concave reflector) converges to the central convex spherical reflector 11, and the reflected light of the central convex spherical reflector 11 is reflected by the first concave spherical reflector 12 or the second concave spherical reflector 13 to form a ring-shaped illumination field.

[0046] refer to Figure 5 The first light beam and the second light beam are converged and reflected by the concave reflector 52 to the convex spherical reflector 11, and the convex spherical reflector 11 reflects the incident light beam to the first concave spherical reflector 12 or the second concave spherical reflector 13. Then the first concave spherical reflector 12 and the second concave spherical reflector 13 respectively reflect the incident light beams to themselves to the object to be measured 7. The reflected light output by the first concave spherical reflector 12 and the reflected light output by the second concave spherical reflector 13 are spliced ​​to form a ring-shaped illumination field of view.

[0047] Optionally, the number of light sources, prism splitting units and optical path transmission units is at least two, and the annular illumination shaping unit modulates the output light beams of at least two light sources into an arc shape and splices them into an annular illumination field to the object to be measured.

[0048] Figure 6 is a schematic diagram of the structure of another dark field annular lighting device provided by an embodiment of the present invention, referring to Figure 6 The light source 1 includes a first light source 101 and a second light source 102, and the prism splitter unit 2 includes a first prism splitter unit 201 and a second prism splitter unit 202. The illumination light beam emitted by the first light source 101 is split into a first light beam and a second light beam by the first prism splitter unit 201, and the first light beam is reflected by the first reflector 31 to the annular illumination shaping unit ( Figure 6 Not shown), the second light beam is reflected by the second reflector 32 to the annular lighting shaping unit; the lighting beam emitted by the second light source 102 is divided into a third light beam and a fourth light beam by the first prism splitting unit 202, the third light beam is reflected by the third reflector 33 to the annular lighting shaping unit, and the fourth light beam is reflected by the fourth reflector 34 to the annular lighting shaping unit, and the first light beam, the second light beam, the third light beam and the fourth light beam are all modulated by the annular lighting shaping unit into arc light beams and can be spliced ​​into an annular lighting field of view.

[0049] Figure 7 is a schematic diagram of the structure of another dark field annular lighting device provided by an embodiment of the present invention, referring to Figure 7 Optionally, the dark field annular lighting device further includes a collimating and homogenizing unit 16, which is located between the light source 1 and the prism splitting unit 2. The illumination light beam output by the light source 1 is collimated by the collimating and homogenizing unit 16 and then incident on the prism splitting unit 2.

[0050] Among them, the light beam emitted by the light source 1 may not be a parallel light beam. In this embodiment, the illumination light beam output by the light source 1 becomes a parallel light beam after passing through the collimating and homogenizing unit 16. The transmission direction of the parallel light beam in the dark field annular lighting device is more controllable and will not diverge during the transmission process.

[0051] Optionally, the dark field annular lighting device further includes an imaging optical path unit 17 and a camera 18 , and the light scattered by the object 7 is incident on the imaging optical path unit 17 , and is converged to an imaging surface of the camera 18 through the imaging optical path unit 17 .

[0052] The structure of the imaging optical path unit 17 may be designed according to actual conditions, for example, it may include a fixed-focus or zoom lens. The embodiment of the present invention does not limit the structure of the imaging optical path unit 17 .

[0053] Figure 8 is a schematic diagram of the structure of another dark field annular lighting device provided by an embodiment of the present invention, referring to Figure 8 , the illumination beam emitted by the light source 1 is divided into a first beam and a second beam by the prism splitting unit 2, the first beam is reflected by the first reflector 31 to the optical path deflection unit 5, the second beam is reflected by the second reflector 32 to the optical path deflection unit 5, and then the first beam and the second beam are incident on the annular illumination shaping unit 6 after passing through the optical path deflection unit 5, the first beam and the second beam are modulated into arc-shaped beams by the annular illumination shaping unit 6 respectively and spliced ​​to form an annular illumination field of view. The annular illumination field of view is irradiated onto the object to be measured 7, and the light scattered by the object to be measured 7 is incident on the imaging optical path unit 17, the imaging optical path unit 17 is arranged above the object to be measured 7, and is arranged on the same side of the object to be measured 7 as the annular illumination shaping unit 6, so that the imaging optical path unit 17 can just receive the light scattered by the object to be measured 7, and then converge the received light scattered by the object to be measured 7 to the imaging surface of the camera 18, so as to image the defects on the surface of the object to be measured 7. Fig. 9 is a three-dimensional structural schematic diagram of a dark field annular lighting device provided by an embodiment of the present invention, with reference to Fig. 9 The optical path deflecting unit 5 and the annular illumination shaping unit 6 have a hollow portion, and the imaging optical path unit 17 can be arranged in the hollow portion of the optical path deflecting unit 5 and the annular illumination shaping unit 6 to receive the light scattered by the object to be measured 7.

[0054] Optionally, the outer contour diameter of the imaging optical path unit 17 is smaller than the minimum inner diameter of the optical path deflection unit 5 and the annular illumination shaping unit 6 .

[0055] Fig.10 is a top view schematic diagram of an imaging optical path unit, an optical path deflection unit and an annular illumination shaping unit provided by an embodiment of the present invention, combined with Fig. 9 and Fig.10As shown, if the diameter of the imaging optical path unit 17 is larger than the minimum diameter of the optical path deflecting unit 5 and the annular illumination shaping unit 6, the imaging optical path unit 17 will block part of the light of the annular illumination formed by the optical path deflecting unit 5 and the annular illumination shaping unit 6, thereby failing to illuminate the measured object 7. Therefore, the diameter of the imaging optical path unit 17 should be smaller than the minimum diameter of the optical path deflecting unit 5 and the annular illumination shaping unit 6, so that the light of the annular illumination formed by the optical path deflecting unit 5 and the annular illumination shaping unit 6 can illuminate the measured object 7. Figure 2 , assuming that the illumination beam is parallel light, the prism splitter unit 2 is a triangular prism with a refractive index of n and a vertex angle of θ, and the illumination beam enters the prism splitter unit 2, then:

[0056]

[0057] sinθ1=n·sinθ2;

[0058] θ3=θ1-θ2;

[0059] n·sinθ3=sinθ4.

[0060] It follows that:

[0061]

[0062] Fig.11 is a partial optical path schematic diagram of a dark field annular lighting device provided by an embodiment of the present invention, with reference to Fig.11 , assuming that the size of the illumination beam incident on the prism splitter unit 2 is 2D1×2D1, and the light spot is symmetrical along the Y axis and the Z axis. The thickness of the prism splitter unit 2 is h, the projection length of the distance from the prism splitter unit 2 to the center position of the light spot of the first reflector 31 and the second reflector 32 on the X axis is D2, the projection length of the light spot center position of the first reflector 31 and the second reflector 32 to the central optical axis of the imaging optical path unit 17 on the X axis is D3, and the angle between the reflection surface of the first reflector 31 and the second reflector 32 and the X axis direction after being projected onto the XOY plane is θ5. At this time, the light spot formed by the light beam emitted by the first reflector 31 and the second reflector 32 irradiating the light path turning unit 5 (not shown in the figure) has a ring-shaped projection 19 on the XOY plane. The inner and outer circle radii of the projection 19 correspond to the position of the light spot on the prism splitter unit 2 at the highest or lowest point on the Z axis. It is assumed here that the width of the projection 19 ring is r1, that is, the difference between the inner diameter and the outer diameter of the projection 19 is r1. When the radius D of the imaging optical path unit 17 satisfies:

[0063]

[0064] The radius of the imaging optical path unit 17 is smaller than the minimum radius of the illumination field.

[0065] Based on the same inventive concept, an embodiment of the present invention further provides an optical detection system, comprising the dark field annular lighting device of any embodiment of the present invention.

[0066] Since the optical detection system provided by the embodiment of the present invention includes any one of the dark-field annular lighting devices provided by the above embodiments, and has the same or corresponding technical effects as the dark-field annular lighting device, it will not be described in detail here.

[0067] The above specific implementations do not constitute a limitation on the scope of protection of this invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of this invention shall be included in the scope of protection of this invention.

Claims

1. A dark field annular lighting device, characterized in that: It includes a light source, a prism light splitting unit, an optical path transmission unit, an optical path deflection unit and a ring lighting shaping unit; The light source is used to output an illumination light beam, and the illumination light beam is split into a first light beam and a second light beam by the prism light splitting unit; The optical path transmission unit comprises a first reflector and a second reflector, wherein the first reflector is used to reflect the first light beam to the optical path deflecting unit, and the second reflector is used to reflect the second light beam to the optical path deflecting unit; The optical path deflection unit is used to change the transmission direction of the first light beam and the second light beam, and transmit the first light beam and the second light beam to the annular lighting shaping unit; The annular illumination shaping unit is used to modulate the first light beam and the second light beam into an arc shape and splice them into an annular illumination field to the object to be measured.

2. The dark field annular lighting device according to claim 1, characterized in that: The optical path transmission unit includes a convex reflector, and the annular illumination shaping unit includes an aconic lens; The first light beam and the second light beam are divergently reflected by the convex reflector to the axle lens, and the axle lens modulates the received light beams into an annular illumination field of view.

3. The dark field annular lighting device according to claim 2, characterized in that: The convex reflector includes a first convex reflector and a second convex reflector, the first convex reflector reflects the first light beam, and the second convex reflector reflects the second light beam; or the convex reflector includes a hollow convex reflector, and the first light beam and the second light beam are both reflected by the hollow convex reflector.

4. The dark field annular lighting device according to claim 1, characterized in that: The optical path transmission unit includes a concave reflector, and the annular illumination shaping unit includes a spherical reflector group; The first light beam and the second light beam are converged and reflected to the spherical reflector group through the concave reflector, and the spherical reflector group modulates the received light beams into a ring-shaped illumination field of view.

5. The dark field annular lighting device according to claim 4, characterized in that: The concave reflecting mirror includes a first concave reflecting mirror and a second concave reflecting mirror, the first concave reflecting mirror reflects the first light beam, and the second concave reflecting mirror reflects the second light beam; or the concave reflecting mirror includes a hollow concave reflecting mirror, and the first light beam and the second light beam are both reflected by the hollow concave reflecting mirror; The spherical reflector group includes a central convex spherical reflector and a first concave spherical reflector and a second concave spherical reflector located on both sides of the central convex spherical reflector. The light reflected by the concave reflector converges to the central convex spherical reflector. The reflected light of the central convex spherical reflector is reflected by the first concave spherical reflector or the second concave spherical reflector to form a ring-shaped illumination field.

6. The dark field annular lighting device according to claim 1, characterized in that: The number of the light source, the prism splitting unit and the optical path transmission unit is at least two, and the annular illumination shaping unit modulates the output light beams of at least two of the light sources into an arc shape and splices them into an annular illumination field to the object to be measured.

7. The dark field annular lighting device according to claim 1, characterized in that: It also includes a collimating and even-light unit, which is located between the light source and the prism splitter unit. The illumination light beam output by the light source is collimated by the collimating and even-light unit and then incident on the prism splitter unit.

8. The dark field annular lighting device according to claim 1, characterized in that: It also includes an imaging optical path unit and a camera. The light scattered by the measured object is incident on the imaging optical path unit and converges to the imaging surface of the camera through the imaging optical path unit.

9. The dark field annular lighting device according to claim 8, characterized in that: The outer contour diameter of the imaging optical path unit is smaller than the minimum inner diameters of the optical path deflecting unit and the annular illumination shaping unit, and the imaging optical path unit is surrounded by the optical path deflecting unit and the annular illumination shaping unit.

10. An optical detection system, characterized in that: It comprises the dark field annular lighting device as described in any one of claims 1 to 9.

Images